First off find the Nightmare Mod list for that. I am right down the offset and then you go to a hex editor and do a search for ever everything that links to that offset. Remember you have to have reverse the order of the numbers in to Little endian. Then you not Down every single ofset that points on the table. Create another event file and use the ORG function on all of the offset you noted down to link to the new table. Ex:
Table offset definition
Don't forget to include it!
Now to insert the new table I recommend you actually choose where you insert it so it will be easier to write down the new offset.
Have no images here as I'm on the phone. Hope someone explain better